1. The Immune System

2. Pathogens
Are organisms or particles such as bacterium, fungus or viruses that have potential to cause disease.
Your body is under constant attack from these pathogens

3. Your immune system tries to prevent these attacks and restore homeostasis
It has three lines of defense

4. First line of Defense
Skin
Mucous membrane
Saliva
Blocks entry into your body

5. Counter attacks The second line of defense
Now the pathogen has slipped through the first line and now your body counterattacks.

6. Some cells attack invaders
Macrophages: a type of white blood cell that kills bacteria one at a time by ingesting them. They travel through the blood stream
Neutrophils: another type of white blood cell that release a bleach like chemical to kill any bacteria

7. Natural Killer T cells: attack only cells that have been infected by microbes, not the microbes themselves. (lead attack against viruses)

8. Proteins that punch holes into bacteria once activated
Complements
Proteins that punch holes into bacteria once activated

9. Inflammation response
You get cut
Area releases chemical signals
It gets red and inflames because this increases blood flow
It promotes migration of the second line of defense

10. Raise body temperature
When the counter attack occurs these white blood cells send messages to the brain to increase body temperature to try to prevent the growth of the pathogen

11. Now the third line you are sick
Two types of response to different pathogens.
Antibody-mediated response (bacteria)
Cell mediated response (virus) cell is infected (produces killer T cells)

12. Antigens: are present on the surface of a pathogen the body then can recognize itself from nonself

13. Antibodies: Produced by plasma B cells they bind to antigens causing a clumping effect and flag others to eat them….